A wide variety of commercial random or dumped packings have been disclosed and used in gas-liquid contacting devices, such as, for example, packings having ring, cylinder, and saddle shapes and designs. Random or dumped packings are typically employed for gas-liquid contacting in chemical processing apparatuses, frequently columns or towers, which are partially or fully filled with the packing to provide intimate gas-liquid contact and wherein liquid is introduced at the upper portion of the column and flows downwardly as a thin film on the surface of the packing, while the vapors are introduced into the lower portion of the tower and ascend through the open spaces in the packing to provide for intimate contact between the liquid film on the surface of the packing and the vapor. Similarly, the packing can be used to obtain intimate contact between two immiscible liquids of different density as the lighter liquid rises while the heavier liquid falls through the bed of packing. Inter-fluid contact is employed for a variety of purposes, such as: mass transfer, for example distillation, scrubbing, stripping, extraction; chemical reaction; heat exchange; and mist elimination or deentrainment.
Thus, prior random packing elements have been formed of a variety of shapes, sizes and of various materials. Historically, the trend in the development of improved random or dumped packing elements has been directed to reducing the pressure drop of the packing. The reduction of pressure drop has usually been accomplished by creating a more open design in the packing in which the flat surfaces are broken up by punching holes, windows or the like in the material in order to reduce the pressure drop of the packing. This gives a packing with a lower pressure drop per unit of mass or heat transfer efficiency.
Expanded sheet material, such as expanded metal sheet material, has been employed in sheet form in a variety of gas-liquid contacting devices, such as packing material for a packed tower, or as a part of a distillation tray, or as a packing material involving a plurality of spaced apart plates. (See for example: U.S. Pat. No. 3,687,818 wherein spaced apart expanded metal sheets are employed as packing material in a distillation column; U.S. Pat. No. 4,028,442 wherein an expanded metal sheet is employed as a tower packing support plate; U.S. Pat. No. 4,184,857 wherein a stripping column contains a plurality of trays, the tray segments being formed of expanded-metal-type slits; and U.S. Pat. No. 4,304,738 wherein a packing material comprises stacked panels of expanded metal, the panels disposed at an angle from each other, the packing material being employed in packed columns and in motionless mixers).
Dumped tower packing elements having a saddle shape have been prepared employing expanded metal. For example, U.S. Pat. No. 4,519,960 discloses a tower packing element for vapor-liquid contact towers wherein the body of the saddle comprises expanded metal or metal that has been perforated, lanced and/or expanded. Also, U.S. Pat. No. 4,537,731 discloses a column packing for gas-liquid devices in the form of a saddle with a net-like matrix structure formed from a plurality of ribs having generally uniform openings.
It is desired to provide for an improved packing, particularly random or dumped packing, for use in gas-liquid or liquid-liquid contact devices, wherein the packing has lower pressure drop, higher capacity, and a lower pressure drop per theoretical stage than those packings currently available and to provide a packing which is easily manufactured at low cost.